The present disclosure relates to an improved device for sharpening the teeth of a chain saw and, more particularly, to a chain saw sharpener that permits the consecutive sharpening of left-hand and right-hand teeth and provides for the accurate, uniform sharpening of the chain saw teeth despite repeated use.
An assortment of portable devices are available for the on-site sharpening of the teeth of a chain saw. However, common problems accompany the use of these sharpening devices, principal among them being the inability to uniformly sharpen both the left-hand and right-hand teeth, and the repeated adjustment of the sharpening device in an attempt to so sharpen the chain saw teeth. Uniformity in the size and shape of the cutting teeth is essential for obtaining a straight, even cut through a work piece. Additionally, many of these devices require a relatively involved setup procedure in which a plurality of jig members must be manipulated before the sharpening process can begin. Because of the numerous adjustments required to set up their devices, the settings of the sharpening devices invariably change during use, resulting in either a constant readjustment of the devices or a non-uniform sharpening of the chain saw teeth. Still further problems exist in these prior devices, such as the inability to sharpen and re-sharpen the chain saw teeth to achieve the full life of the chain saw teeth. Indeed, in some cases, the chain saw teeth can only be sharpened to a certain degree (i.e., only a limited amount of material can be removed) limited by the configuration and capability of the sharpening device itself. In some cases, when the material of the chain saw teeth is reduced beyond a certain point, but not beyond what one would consider as still having usable material that would extend the life of the chain saw chain, the sharpening devices used can begin to cut into the structure securing the chain saw teeth in place, thus making any further sharpening of the chain saw teeth impossible without destroying the sharpening device or its component parts.
Many prior sharpening devices can first sharpen all the teeth of a like hand (i.e., either all the left-hand teeth or all the right-hand teeth) and then the sharpener can be readjusted to sharpen the teeth of the opposite hand. However, when using cumbersome jig-type setups, this requires that the jig members be repeatedly manipulated for sharpening the teeth of opposite hands. Further, the readjustment after first sharpening all the teeth of one hand often results in an undesirable variance between the teeth of the opposite hands. An additional series of relatively complicated adjustments also must be made to cut the depth gauge portions of the teeth.
To add to the difficulty and limitations of prior sharpening devices, the rake angle of the teeth on different makes of saw chains often varies, the rake angle typically being 25°, 30°, or 35° with respect to a reference line perpendicular to the cutting bar of the chain saw. However, many prior sharpening devices are able to sharpen the teeth of only one rake angle, thus limiting their utility.
Other sharpening devices exists that allow for the sharpening the teeth of opposite hands and of different rake angles. However, these often require extensive machining to manufacture, thus making such sharpening devices very expensive. Further to allow for the sharpening of chain saw teeth of different rake angles, an entire section of the sharpener must be removed and replaced, thus adding to the cost and complexity of the sharpening device.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.